Illuminating device for cinematographic projection apparatus



Aug; 17 ,1926.

A. l.. Vv. c. DEBBIE 'ILLUIINATIIG Davies lion crnsn'roannnrc PnoJsc'rIon umwrus l Fund June s. 1924 i :Patented Aug. 17,1926.

Alas

UNITED STATES 1,596,481 PATENT OFFICE.

ANDRE LEON VICTOR CLEMENT DEBBIE, OFOPAEIS, FRANCE.

ILLUHUATING DEVICE EOE CINEHATOGEAPHIQ PROJECTION APPARATUS.

Appunti mea :im a, um, semi n. 71u53, and in France :une 1a, ma.

It frequently happens that cinematograih or films, and chiefiy those which are used educationalA purposes, are projected on the screen one vlew at a time, and the duration of each View may thus be considerable. But it is Well known that such cases ma present some danger of ignition of the in the case of a lamp havin aat luminous intensity. As on the otv er anditis advantageous to be abley to change over instantly from the single view projection to the usual projection, various removable devices have been roposed for reducing the brillianc of the amp in the case of separate views. `or instance it is the general practice to interpose a transparent screen between the lamp and the film; in some cases a resistance is mounted in the circuit of the lamp.- But the various arrangements employed have the drawback of occasioning a considerable consumption of current. y

In my invention, the projection lamp is an incandescent .lam comprising a plurality of filaments adapte for simultaneous connection in the circuit where the maximum brilliancy is desired,'or for separate connection for a reduced brillianc The said filaments Amay have the same i uminating power or preferably each filament may'have-a di erent illuminating power. y

In this manner, I am enabled'to reduce. the brilliancy of the lamp and consequent- 'lyto diminlsh the heat produced A,by the same, according to the time of projection Fig. 2 is a diagrammatic view of an auto matic operating means for the lamp.

The base 1 of the lamp 2 is traversed by four wires 3, 4, 5, 6 whereof the wires 3 and 5 may be connectedv to the positive -pole of .the source of current and the wires 4 and 6 to the nega-tive pole. The wires 3 and 4 are connected to a filament 7 and the wires 5 and 6. to a second filament 8. In the embodiment herein represented, the brilliancy of the filament 8 is less than that of the filament 7; these two filaments are united by a filament 9 disposed between the wires 4 and 5.

If the positive pole of the supply circuit.v

hand-controlled to l bel connected to the wire 3 and the negative to the wire 4, the filament 7 will be solely raised to incandescence, but the low power filament S will on the contrary be the one vt0 in use if the poles are connected to the ',wires 5 and 6; but by connecting the wires 3 and 6 to the poles, the current will now pass that the resulting brilliancy shall be greatn er when the projection apparatus is working at a higher speed. In the case of automatic operation the automatic control may be based upon an arrangement depending upon centrifufral force and actuating a circuit-breaking device whereby. the lampfilaments will be illuminated according to the brilliancy desired.

Such an automatic control arrangement is shown in Fig. 2 in which the centrifugal regulator 10 revolving round shaft 11 controlled by the operating shaft of the apparatus actuates a switch 12 by means of the slide 13 mounted loosely on shaft 11 and engaging with notch 14 of switch handle.

It is eas to see-thatwhen the speed of shaft 11 1ncreases, the brilliancy of the lamp increases also as the slide 13 movin towards the left; connects first wires 3 an 4, then 5 and 6 and finally 3 and 6. The I usual compensating resistances 15and 16 are inserted in the wires and operate to keep the intensity of the current constant regardless of these connections is the one which as exlained hereinabove, gives increasing bril- 'ancy. Of course, the switch could be also produce the same result. What I cla-im is:. 1. In a cinematographic apparatus the combination of an electric lamp,'means for unrollin the film, an electric circuit-branch I lines fe by said circuit, a plurality of filaments disposedf/iin said lamp and inserted in said branch lines, means whereby the num-` ber of filaments" used increases with the speedy of unrolling of film.

2. Inl a .cinemato aphic apparatus the combination of an e ectric lamp, means for unrolhn the film, an electric circult, branch lines fe by said'circuit, a pluralityv of laf ments disposed in saidv lamp and inserted in ments disposed 1n said lamp and inserted in said branch lines, automatic means whereby said, branch lines, a switch controlling said 10 the number of filaments used increases withbrunch lines, zi centrifugal regulator actuthe speed of unrolling` of film. ated by the cinematographic apparatus and 5 3. In a cinematographic apparatus the controlling said switch.

combination of an electric lamp, means for 111 Witness whereof I have hereunto set my lunrolling the lm, an electric circuit, branch hund.

lines fed by said circuit, a plurality of 1a- 'ANDRE LEON vlcTox CLEMENT Drame. 

